sually potent in this world. Among
these rationalistic men of Germany I found conscientiousness in work
as much insisted on as it could be among theologians. And why, since
they had not the rewards or penalties of the theologian to offer to
their disciples? Because they assumed, and were justified in
assuming, that those whom they addressed had that within them which
would respond to their appeal. If Germany should ever change for
something less noble the simple earnestness and fidelity to duty,
which in those days characterised her teachers, and through them her
sons generally, it will not be because of rationalism. Such a
decadent Germany might coexist with the most rampant rationalism
without their standing to each other in the relation of cause and
effect.

My first really laborious investigation, conducted jointly with my
friend Professor Knoblauch, landed me in a region which harmonised
with my speculative tastes. It was essentially an enquiry in
molecular physics, having reference to the curious, and then
perplexing, phenomena exhibited by crystals when freely suspended in
the magnetic field. I here lived amid the most complex operations of
magnetism in its twofold aspect of an attractive and a repellent
force. Iron was attracted by a magnet, bismuth was repelled, and the
crystals operated on ranged themselves under these two heads. Faraday
and Pluecker had worked assiduously at the subject, and had invoked
the aid of new forces to account for the phenomena. It was soon,
however, found that the displacement in a crystal of an atom of the
iron class by an atom of the bismuth class, involving no change of
crystalline form, produced a complete reversal of the phenomena. The
lines through the crystal which were in the one case drawn towards the
poles of the magnet, were driven, in the other case, from these poles.
By such instances and the reasoning which they suggested,
magne-crystallic action was proved to be due, not to the operation of
new forces, but to the modification of the old ones by molecular
arrangement. Whether diamagnetism, like magnetism, was a polar force,
was in those days a subject of the most lively contention. It was
finally proved to be so; and the most complicated cases of
magne-crystallic action were immediately shown to be simple mechanical
consequences of the principle of diamagnetic polarity. These early
researches, which occupied in all five years of my life, and
throughout w